Flow Battery Apparatus with Shunted Current Repressed and Method Thereof

ABSTRACT

A flow battery apparatus is provided with shunted currents repressed. The apparatus has a positive electrode device, a negative electrode device and a plurality of gas-gap devices. Gas-gap devices are separately set between branching channels and inlet and outlet manifolds of positive and negative electrodes. Each of the branching channels separately has an inserting tube to be inserted into one of the gas-gap devices. The diameter of the inserted vessel of gas-gap devices is bigger than the diameter of the inserting tube connected to a corresponding one of the branching channels. Thus, working liquids transferred to the positive and negative electrodes are segregated with coordination of the gas-gap devices. Only air spaces and discrete liquid drops are left between separated parts of the working liquids. Thus, shunted currents are repressed by preventing conductive paths from being formed between the positive and negative electrodes.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to repressing shunted current; moreparticularly, relates to repressing shunted currents by preventingconductive paths of electrolytes from being formed between any pair ofunit cells stacked in series to compose a corresponding battery, whereflows of the electrolytes are segregated with gas gaps at positionsbetween diverging manifolds and their corresponding branch channelsbefore inletting unit cells, as well as at positions between flow-streamchannels after outletting the unit cells and their correspondingconverging manifolds while the gas gaps restrain shunt currents alongthe electrolytes between any pair of the unit cells with the shuntcurrent repressed.

DESCRIPTION OF THE RELATED ARTS

Redox flow batteries have been studied for decades. Shunt current energyloss mostly occurred at flow batteries structured with unit cellsstacked in series.

A general serial structure of flow battery comprises a series of unitcells. Each unit cell at least comprises positive and negativeelectrodes (usually plates), working liquids (usually electrolytes) andan ion exchange membrane. Working liquids flow onto each surface ofelectrode plates of the unit cells through branching channels with thehelp of diverging manifolds connected, and then leave the electrodesthrough the branching channels with the help of converging manifoldsconnected. It is quite often to form shunted currents owing to theworking liquids conducted and the potential differences between the flowbattery units. Hence, shunt current energy loss may occur and theefficiency of the flow battery becomes low.

To deal with the problem, one method is to apply protection circuits tothe flow battery for repressing shunted currents. However, circuitcomplexity is thus increased and more energy is consumed by theadditional circuits. The efficiency for repressing shunted currents isnot good enough. Another method is to change the paths of the workingliquids to reduce power loss. But, this will increase the structuralcomplexity of the flow battery with limited efficiency. Another methodis to integrate the above two methods. Nevertheless, the structurebecomes more complex with power loss remained high and improvementunattainable.

Hence, the prior arts do not fulfill all users' requests on actual use.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to repress shunted currentsby preventing conductive paths of working electrolytes from being formedbetween any pair of unit cells, where the liquid flow streams betweenany pair of unit cells are segregated with gas gaps, so that very few ofelectric or ionic conduct of working liquid might cross the segregatedgas gaps; working liquids is allowed to cross the gas-gap by discretetransferring with the shapes of droplets or bulky-drops, which do notreach both side of upper flow stream and lower flow streamsimultaneously, to proceed the liquid flow without electric or ionicconduct to ensure the supply of working liquids reach each of unit cellsof working; the segregating gas gaps are located at the positionsbetween diverging manifolds and subsidiary flow streams before theinlets of each of unit cells as well as at the positions between theflow streams after the outlets of each of unit cells and convergingmanifolds to ensure the liquid flow streams between any pair of unitcells were segregated;

Another purpose of the present invention is to flow the working liquidsof upper streams, i.e. before gas-gap devices, as falling dropsdiscretely through the segregating gas gap onto the surface of bottomflow without connecting both of the upper and the bottom flows at anymoment, where the conductive paths of working liquids that causes theshunt currents are cut off; meanwhile, the gas gaps do not intervene theworking liquids flow through any of unit cells in batteries; thestructure of the gas-gap device is that at least one channel holder (atube, for example) inserts into the inside space of another channelholder in larger dimension through the top wall (or upper part of theinserted channel holder) to compose a total flow channel without leak;the working liquids flow in a shape of droplet (or bulky-drop) out ofthe narrower channel holder through the gas space of the inside of thewider channel holder onto the surface of bottom flows; the flowing dropsnever connect physically with the liquid of upper flow in the narrowchannel holder and with the liquid of bottom flow in the wider channelholder in a meantime simultaneously; thus, current conductive is notable to access between the upper and the lower liquid flows since eachof the channel holders is made of an insulate material; in order toincrease the effect of preventing splashed dripping liquid from formingconductive connection, some fins attached on the wall can be applied;and, to improve the effect of making the flow droplets (or bulky-drops),a pulsatile or reciprocating flow pumping manner can be used; and, forcompact reason, the gas-gap device can be also applied to the manifoldswith common inserted vessel.

To achieve the above purposes, the present invention is a flow batteryapparatus with shunted current repressed, comprising a positiveelectrode device, a negative electrode device and a plurality of gas-gapdevices, where the positive electrode device comprises a plurality ofpositive electrodes, a plurality of first branching channels, an inletdiverging manifold and an outlet converging manifold; the firstbranching channels are separately connected with the positive electrodesat two sides; the inlet diverging manifold is connected to the firstbranching channels to be connected with the positive electrodes at oneside of the positive electrodes; the outlet converging manifold isconnected to the first branching channels to be connected with thepositive electrodes at the other side of the positive electrodes; thenegative electrode device comprises a plurality of negative electrodes,a plurality of second branching channels, an inlet diverging manifoldand an outlet converging manifold; the second branching channels areseparately connected with the negative electrodes at two sides; theinlet diverging manifold is connected to the second branching channelsto be connected with the negative electrodes at one side of the negativeelectrodes; the outlet converging manifold is connected to the secondbranching channels to be connected with the negative electrodes at theother side of the negative electrodes; the gas-gap devices is locatedbetween the first and the second branching channels, the inlet divergingmanifolds and the outlet converging manifolds; each of the first andsecond branching channels is connected with an inserting tube to beseparately inserted into an inserted vessel of the gas-gap devices witha diameter of the inserting tube connected with the first and secondbranching channels smaller than a diameter of the inserted vessel of thegas-gap devices.

Accordingly, a method for novel flow battery apparatus with shuntedcurrent repressed is obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood from the followingdetailed description of the preferred embodiment according to thepresent invention, taken in conjunction with the accompanying drawings,in which

FIG. 1 is the perspective view showing the preferred embodimentaccording to the present invention;

FIG. 2 is the view showing the first state-of-use of the gas-gap device;

FIG. 3 is the view showing the connection of the first state-of-use ofthe gas-gap device to the inlet diverging manifold;

FIG. 4 is the view showing the connection of the first state-of-use ofthe gas-gap device to the outlet converging manifold;

FIG. 5 is the view showing the second state-of-use of the gas-gapdevice;

FIG. 6 is the view showing the third state-of-use of the gas-gap device;and

FIG. 7 is the explosive view showing the flow battery having theelectrode-imbedded-plastic-frames with gas-gap devices.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The following description of the preferred embodiment is provided tounderstand the features and the structures of the present invention.

Please refer to FIG. 1˜FIG. 4, which are a perspective view showing apreferred embodiment according to the present invention; a view showingthe first state-of-use of the gas-gap device; and views showingconnections of a first state-of-use of the gas-gap device to an inletdiverging manifold and an outlet converging manifold. As shown in thefigures, the present invention is a flow battery apparatus with shuntedcurrent repressed. As is known, a traditional flow battery comprises aplurality of unit cells. Therein, a first unit cell of the flow batteryhas a terminal plate with a positive electrode and a negative electrodefrom one side of an adjacent bipolar plate; the bipolar plate has twoelectrodes having different polarity in each side and the electrodesbelong to adjacent two unit cells; a last unit cell of the flow batteryhas a terminal plate with a negative electrode and a positive electrodefrom one side of adjacent bipolar plate; all the other unit cells of theflow battery has a positive electrode from one side of bipolar plate anda negative electrode from the other side of adjacent bipolar plate; andmembranes are located between the plates with flowing electrolytes. Thepresent invention comprises a positive electrode device 1, a negativeelectrode device 2 and a plurality of gas-gap devices 3. For simplicity,all positive electrodes are indicated as the positive electrode device1, all negative electrodes are indicated as the negative electrodedevice 2 and membranes are not shown.

The positive electrode device 1 comprises a plurality of positiveelectrodes 11; a plurality of first branching channels 12,13 separatelyconnected with the positive electrodes 11 at two sides; an inletdiverging manifold 14 connected with the first branching channels 12 tobe connected with the positive electrodes 11 at one side; and an outletconverging manifolds 15 connected with the first branching channels 13to be connected with the positive electrodes 11 at the other side.Therein, each of the first branching channels 12,13 has an insertingtube 32 made of an insulating material. Or, each of the gas-gap devices3 has an inserted vessel 31 made of an insulating material. Or, acomponent made of an insulating material is set at each place where theinserting tube is inserted into the inserted vessel 31 of the gas-gapdevices 3. Thus, the conductive of shunt current is prevented bygas-gap, within which are falling drops of working liquids betweenoutlet of upper flow in the inserting tube 32 and surface of bottom flowin the inserted vessels 31 of the gas-gap devices 3. The droplets do notconduct because both flows at upper and bottom sides do not reach eachother simultaneously.

The negative electrode device 2 comprises a plurality of negativeelectrodes 21; a plurality of second branching channels 22,23 separatelyconnected with the negative electrodes 21 at two sides; an inletdiverging manifold 24 connected with the second branching channels 22 tobe connected with the negative electrodes at one side; and an outletconverging manifold 25 connected with the second branching channels 23to be connected with the negative electrodes 21 at the other side.Therein, each of the second branching channels 22,23 has an insertingtube 32 made of an insulating material. Or, the gas-gap devices 3 has aninserted vessel 31 made of an insulating material. Or, a component madeof an insulating material is set at each place where the inserting tube32 is connected with the inserted vessel 31 of the gas-gap devices 3.Thus, the conduction of shunt current is prevented by gas-gap, withinwhich are falling drops of working liquids between outlet of upper flowin the inserting tube 32 and surface of bottom flow in the insertedvessel 31 of the gas-gap devices 3. The droplets do not conduct becauseboth flows at upper and bottom sides do not reach each othersimultaneously. The above describes the method of repressing shuntcurrent.

The gas-gap devices 3 are made of at least a part of insulatingmaterials and are separately set between the first and second branchingchannels 12,13,22,23; and the inlet diverging manifolds 14,24 and outletconverging manifolds 15,25 of the positive and negative electrodes11,21. Each of the first and second branching channels 12,13,22,23 hasan inserting tube 32 to be inserted into the inserted vessels 31 of thegas-gap devices 3 from upper side and do not touch bottom of theinserted vessels 31 of the gas-gap devices 3, where diameters of theinserting tubes 32 connected to the first and second branching channels12,13,22,23 are smaller than diameters of the inserted vessels 31 of thegas-gap devices 3, to ensure that droplets out of the inserting tubes 32do not touch side walls of the inserted vessels 31. Nevertheless, forincreasing effect of preventing splashed dripping liquid from formingconductive connection, each of the inserting tubes 32 extended from thefirst and second branching channels 12,13,22,23 has a plurality of fins321. The fins 321 are made of an insulating material and set at outeredge of each place where the inserting tube 32 of each of the first andsecond branching channels 12,13,22,23 is inserted into one of theinserted vessels 31 of the gas-gap devices 3; and, each one of theinserted vessels 31 of the gas-gap devices 3 has a plurality of fins 311made of an insulating material set on an inner surface of the one of theinserted vessels 31 of the gas-gap devices 3. On using the presentinvention with the gas-gap devices 3, the number and the shapes of theinserting tubes 32 and the inserted vessels 31 of the gas-gap devices 3are provided according to requirements, not restrained by shapes ofround pipes, oval pipes, square pipes, polygonal pipes or shrinking(expending) pipes in different diameters. No matter how the number andshapes are changed, the key of the gas-gap devices is that the dropletsout of the inserting channel holders (tubes) should not reach both theupper flow and the bottom flow simultaneously.

Please further refer to FIG. 5˜FIG. 7, which are a view showing a secondstate-of-use of the gas-gap device; a view showing a third state-of-useof the gas-gap device; and an explosive view showing a flow batteryhaving electrode-imbedded-plastic-frames with gas-gap devices. As shownin FIG. 5, a state-of-use of a gas-gap device has a common insertedvessel 31 for a plurality of inserting tubes 32. And the common vessel31 has several drain rooms, each of the drain rooms receives the fallingdrops from the respective inserting tube 32 positioned above. The resultis the same as what is provided by FIG. 3. A benefit for this gas-gapdevice with a common inserted vessel is that it can be used as a compactdiverging manifold with gas-gap built-in, and then makes the flowbatteries compact.

As shown in FIG. 6, similarly, another state-of-use of gas-gap deviceshas a common inserted vessel 31 for a plurality of inserting tubes 32.The common vessel has only one drain room which receives the fallingdrops from all inserting tubes 32 above. The result is the same as whatis provided by FIG. 4. A benefit is that it can be used as a compactconverging manifold with gas-gap built-in, and also makes the flowbatteries compact.

As shown in FIG. 7, for convenience of assembling a practical flowbattery, plastic frames with imbedded electrodes are often used. Anelectrode-imbedded-plastic-frame type flow battery is stacked withseveral unit cells with common inlet ports and outlet ports. The flowbattery 5 comprises a positive electrode device 51, a negative electrodedevice 52 and a plurality of gas-gap devices 53. The positive electrodedevice 51 is similar to the positive electrode device 1 shown in FIG. 1,but specified in the flow battery 5 shown in FIG. 7. Please note that,later in this document, the first digital (i.e. 5) of the series numberof notation will stand for a similarity of the rest number used in FIG.1 if exists, but used specifically in the flow battery 5 only. Thepositive electrode device 51 comprises a plurality of positiveelectrodes 511, a plurality of first branching channels 512,513, aninlet diverging manifold 514 and an outlet converging manifolds 515. Thepositive electrodes 511 are similar to the positive electrodes 11 shownin FIG. 1. The negative electrode device 52 is similar to the negativeelectrode device 2 shown in FIG. 1. The negative electrode device 52 hasa plurality of negative electrodes 521. Each of the electrodes 511,521is imbedded in a plastic frame 551. Among the adjacentelectrode-imbedded plastic-frames 551 are the corresponding carbon feltswith membranes 552, and packings 553 (not shown in FIG. 1 forsimplicity). The first branching channels 512,513 are separatelyconnected with the positive electrodes 511 at two sides. The connectionzones between the positive electrodes 511 and the first branchingchannels 512,512 are designed for better distribution of workingliquids, which is not further described for not on the purpose of theinvention for repressing shunted current. The inlet diverging manifold514 is connected with the first branching channel 512. The outletconverging manifold 515 is connected with the first branching channel513. The gas-gap devices 53 are set between the diverging manifold 514and the first branching channels 512, and between the convergingmanifold 515 and the first branching channels 513. Inserting tubes 532are connected to the first branching channels 512,513 to be insertedinto the inserted vessels 531 from an upper side and do not touch bottomof the inserted vessels 531 for leaving a distance at least thatdroplets do not connect both side of the inserted vessels 531 and theinserting tubes 532 simultaneously. It results in that very few ofelectric or ionic conduction of working liquid might cross gas gaps, andthen shunted current is repressed. The above are descriptions about thefirst branching channels, the gas-gap devices and manifolds of positive.Similar designations applied for those of the negative electrodes.Although the drawings were covered in FIG. 7, the same results isavailable. Thus, the repression of shunted current is accomplished.Accordingly, a novel flow battery of electrode-imbedded-plastic-framestype with shunted current repressed is obtained.

To sum up, the present invention is a flow battery apparatus withshunted current repressed, where working liquids transferred to positiveand negative electrodes are segregated with coordination of gas-gapdevices and only few falling drops of working liquids go through gasspaces at a moment are left between segregated parts of the workingliquids for repressing shunted currents by preventing conductive pathsfrom being formed between the positive and negative electrodes of anypair of unit cells.

The preferred embodiment herein disclosed is not intended tounnecessarily limit the scope of the invention. Therefore, simplemodifications or variations belonging to the equivalent of the scope ofthe claims and the instructions disclosed herein for a patent are allwithin the scope of the present invention.

What is claimed is:
 1. A flow battery apparatus with shunted current repressed, comprising: a positive electrode device, said positive electrode device comprising a plurality of positive electrodes; a plurality of first branching channels, said first branching channels being separately connected with said positive electrodes at two sides; an inlet diverging manifold, said inlet diverging manifold being connected to said first branching channels to be connected with said positive electrodes at one side of said positive electrodes; and an outlet converging manifold, said outlet converging manifold being connected to said first branching channels to be connected with said positive electrodes at the other side of said positive electrodes; a negative electrode device, said negative electrode device comprising a plurality of negative electrodes; a plurality of second branching channels, said second branching channels being separately connected with said negative electrodes at two sides; an inlet diverging manifold, said inlet diverging manifold being connected to said second branching channels to be connected with said negative electrodes at one side of said negative electrodes; and an outlet converging manifold, said outlet converging manifold being connected to said second branching channels to be connected with said negative electrodes at the other side of said negative electrodes; and a plurality of gas-gap devices, said gas-gap devices being located between said first and said second branching channels, said inlet diverging manifolds and said outlet converging manifolds, wherein each of said first and second branching channels is connected with an inserting tube to be separately inserted into an inserted vessel of said gas-gap devices with a diameter of said inserting tube connected with said first and second branching channels smaller than a diameter of said inserted vessel of said gas-gap devices.
 2. The flow battery apparatus according to claim 1, wherein said inserting tube connected with said first and second branching channels has a coating made of an insulating material.
 3. The flow battery apparatus according to claim 1, wherein said inserting tube connected with said first and second branching channels is made of an insulating material.
 4. The flow battery apparatus according to claim 1, wherein an insulating material is located at each joint between said first and second branching channels, said inserting tube and said inserted vessel.
 5. The flow battery apparatus according to claim 1, wherein said inserted vessel of said gas-gap devices contains an insulating material.
 6. The flow battery apparatus according to claim 1, wherein said gas-gap devices are made of at least a part of insulating materials.
 7. The flow battery apparatus according to claim 1, wherein each one of said first and second branching channels, said inlet diverging manifold, said outlet converging manifold, said inserting tube and said inserted vessel is selected from a group consist of a round pipe, an oval pipe, a square pipe, a polygonal pipe, a shrinking pipe, an expanding pipe and a deform pipe.
 8. The flow battery apparatus according to claim 1, wherein said inlet diverging manifold has a driving unit to deliver liquid in a manner selected from a group consist of a pulsatile manner and a reciprocating manner.
 9. The flow battery apparatus according to claim 1, wherein said inserted vessel is a common vessel to be inserted with said inserting tubes.
 10. The flow battery apparatus according to claim 9, wherein said common vessel is connected to said first and second branching channels with said inlet diverging manifold and said inlet diverging manifold and has a plurality of individual rooms.
 11. The flow battery apparatus according to claim 9, wherein said common vessel is connected to said first and second branching channels with said outlet converging manifold and said outlet converging manifold and has at least one room in common.
 12. The flow battery apparatus according to claim 1, wherein each of said positive and said negative electrodes is imbedded in a plastic frame.
 13. The flow battery apparatus according to claim 12, wherein said plastic frame has a plurality of flow channels.
 14. The flow battery apparatus according to claim 13, wherein each of said flow channels has a gas-gap device.
 15. The flow battery apparatus according to claim 1, wherein working liquids are segregated with coordination of said gas-gap devices on being delivered to said positive and negative electrodes and only gas spaces and discrete liquid drops are left between separated parts of said working liquids to repress shunted currents by preventing conductive paths from being formed between said positive electrodes and said negative electrodes. 